1. Field of the Invention
This invention relates to solid state miniature mass spectrometers, and more particularly to a miniature mass spectrometer test system for the analysis of chemical and solid particles of either low vapor pressure chemicals or biological materials, such as toxins or spores.
2. Description of Related Art
A mass spectrometer is a device that permits rapid analysis of an unknown sample of material to be analyzed. A small amount of the sample is introduced into the mass spectrometer where it is ionized, focused and accelerated by means of magnetic and/or electric fields toward a detector array. Different ionized constituents of the sample travel along different paths to the detector array in accordance with their mass to charge ratios. The outputs from the individual detector elements of the array provide an indication of the sample's constituents.
Industrial mass spectrometers are generally large, heavy and expensive, and therefore, a need exists for a miniature, relatively inexpensive light-weight solid state mass spectrometer for use by the military, homeland security personnel, hazmat crews, industrial concerns and the like to test for the presence of dangerous substances in the immediate environment.
A typical miniature mass spectrometer is shown and described in the present assignee's U.S. Pat. No. 5,386,115 entitled “Solid State Micro-Machined Mass Spectrograph Universal Gas Detection Sensor”, issued to Carl B. Freidhoff et al. on Jan. 31, 1995. Basically the miniature mass spectrometer disclosed in U.S. Pat. No. 5,386,115 is comprised of two semiconductor substrates joined together by an epoxy seal. Each half includes intricate cavities formed by a lithograph process for mounting and housing the components of the mass spectrometer.
In the above cross referenced related application U.S. Ser. No. 11/260,106, there is disclosed an improved MEMs mass spectrometer for analyzing a gas sample and comprises apparatus having metal walls connected between an elongated lid and base member fabricated on a semiconductor chip, similar to the mass spectrometer disclosed in U.S. Pat. No. 5,386,115, with the walls defining a plurality of interior chambers including sample gas input chambers, an ionizer chamber, a plurality of ion optics chambers and an ion separation chamber. A detector array at the end of the ion separation chamber includes a plurality of detector elements positioned along two parallel lines and arranged to intercept all of the ionized beams produced in the device.